Article on doing diet trials for allergies from June AKC newsletter
Maybe someone will find this helpful:
Caroline Coile is the author of more than 30 books about dogs, and is a two-time Canine Health Foundation Award winner. He’s scratching and licking, keeping you awake, ruining his show coat, and giving himself a handy excuse for breaking that stay. It’s driving you crazy—imagine how he must feel.
We most often associate allergies with sneezing and respiratory problems in people, but in dogs, allergies are most often associated with the skin and gastrointestinal (GI) tract. About 10 to 15 percent of dogs with food allergies will have both skin and GI signs, and about 20 to 30 percent of dogs with food allergies will also have itchy skin from other non-food allergies.
GI signs are most often loose stools, with an average of three a day. Vomiting and belching can also be signs. A skin sign is usually itchiness, and it appears the same as itchiness due to other allergies.
According to one recent study, nearly 8 percent of dogs presented to a referral dermatology practice had food allergies, which represented about a third of all the dogs presented there with allergic skin disease. “Ears and rears” is sometimes used to refer to the characteristic location of itchiness, though it’s actually a little more widespread than just those regions. In one study, dogs with food allergies suffered from itchy ears in 80 percent of the cases (and in fact, only the ear was affected in a quarter of all cases); itchy feet in 61 percent; itchy groin region in 53 percent; and itchy armpits, anterior foreleg, or eye regions in about 35 percent of cases. Secondary ear- and skin infections often arise from self-inflicted trauma from scratching and chewing. These infections must be treated along with removal of the offending food.
Some breeds, such as Cocker Spaniels, Labrador Retrievers, Golden Retrievers, German Shepherd Dogs, Poodles, and Chinese Shar-Pei, may be at greater risk for food allergies, though they can appear in any breed. Allergies can appear at any age, but most dogs have been eating the offending food for two years before signs of allergy appear. Some develop signs as early as two months of eating the offending food, but allergic reactions are not something that normally appear immediately after introducing a new food. But once symptoms appear, their onset is often sudden and serious.
After ruling out other possible causes (such as flea allergies, scabies, ringworm, and demodex), trial diets can be undertaken. Blood tests exist but are unreliable to the point of uselessness. Three-quarters of non-allergic dogs in one study tested positive for multiple food ingredients, none of which caused any allergic signs in the dogs in real life.
Trial diets consist of foods with unique proteins and limited ingredients. Commercial veterinary diets with novel protein sources have made home cooking unnecessary, but you could prepare your dog’s food following various veterinary-approved recipes. The important thing to remember is that novel-protein diets must have protein sources that the dog hasn’t been exposed to beforehand. Possible protein sources include tuna, salmon, rabbit, game meats, pinto beans, and garbanzo beans; possible carbohydrate sources include yams, pumpkin, oats, barley, and quinoa. Because home-prepared trial diets usually use only two ingredients (one protein and one carbohydrate), they’re not adequate for long-term feeding.
Commercial veterinary diets include fish, duck, venison, rabbit, kangaroo, modified soy, or modified chicken livers as protein sources. Many years ago lamb and rice–based foods were introduced to dogs who developed allergies to the more common dog-food protein sources, such as beef and chicken. Because most dogs had not been exposed to lamb in their diets, they had not yet developed allergies to it and often remained allergy-free for months to years. Lamb-and-rice diets gained the reputation of being hypoallergenic and increased in popularity. But there is nothing inherently hypoallergenic in these foods; their success lies in the fact that dogs had not eaten them before. Now their popularity as staple diets has negated their efficacy as a fallback or trial diet for dogs with food allergies. Make a list of every food your dog has eaten in the past, and make sure it’s not one of the ingredients of the novel diet. For dogs who eat a lot of variety, this can be challenging.
An alternative is to feed a food containing hydrolyzed proteins—conventional proteins broken down into molecules too small to stimulate the immune system. Hills Z/D, Purina HA, and Royal Canin Hypoallergenic all make use of hydrolyzed proteins.
Commercial hypoallergenic foods often contain increased levels of omega 3 fatty acids or decreased omega 6 to omega 3 fatty-acid ratios to decrease skin inflammation and itching.
During the trial, the dog must eat only the trial food—no treats, table scraps, chewies, or even chewable pills unless they contain only the same ingredient sources as the trial diet. Read the ingredients of any treat or human food you may wish to feed; for example, rice cakes often contain wheat as well. You must be diligent about the dog’s self-feeding habits; no foraging in the garbage pail or under the baby’s high chair. If you have more than one pet, feed them separated or crated. Make sure your dog has no access to cat or dog feces he might eat, or even another pet’s vomit. Many owners find sticking to the diet is difficult, and some dogs rebel at the limited variety and lack of customary treats. You can try putting pieces of the dry trial-diet kibble in a food-delivery toy to break the monotony. Or if feeding a canned trial food, slice it up and bake it to make dog cookies. Family and friends must understand that breaking the diet will only prolong the trial.
In past years the trial lasted for four weeks, but some recent studies have found that only a quarter of dogs with food allergy will respond in this time. About 80 percent will respond in six weeks. Generally if a dog has not responded in nine weeks he probably won’t, but trials may still be conducted for 10 to 12 weeks. Cocker Spaniels and Labrador Retrievers tend to take longer to respond than other breeds.
Consider taking weekly photos of your dog or keeping a journal so you’ll have a better idea of how he’s improving. Some dogs have such terrible itching at the beginning of the trial that a corticosteroid may be given to provide temporary relief. If so, you must wait long enough for the effects of the steroid to wear off before attributing any improvement to the food.
At the end of the trial, the dog is presented with his former suspect diet to make sure the symptoms didn’t go away for some other non–diet related reason. If the dog is allergic to that diet, symptoms should reappear from a few hours up to a week afterward. At this point the dog can be placed back on the trial diet as a regular diet, or suspected ingredients can be added to the diet one at a time, waiting at least two weeks after the dog is asymptomatic before adding another.
Most dogs react to one or two allergens; about 20 percent react to more. There’s a greater chance that dogs react to animal products from the same species (milk and meat from cattle, for example) or from related species (cattle, sheep, and deer, for example).
Diet trials are inconvenient and tedious. But compared to your dog’s discomfort, they’re a small price to pay to identify the culprit. Unfortunately there is no cure for food allergies—except to avoid the offending foods.
This article first appeared in the June, 2011 AKC Gazette and is reprinted with permission. To subscribe to AKC Family Dog please go to: akc.org/pubs/index.cfm]American Kennel Club - AKC Magazines.
Last edited by cali~jenn; 08-19-2011 at 07:55 AM.
Reason: link removal
Re: Article on doing diet trials for allergies from June AKC newsletter
Thanks for the article. I wouldn't try their recommended kibbles but they get their point across.
Re: Article on doing diet trials for allergies from June AKC newsletter
That's what I thought, too.
Originally Posted by savemejeebus
August, not June newsletter. Oops!